Based on climate and climate change scenarios simulated by 28 CMIP5 (Coupled Model Intercomparison Project Phase 5) models and observations of temperature and precipitation, the authors evaluate the performance of the 28 CMIP5 models in simulating temperature and precipitation in East China and Shanghai. Future changes in extreme temperature and precipitation events under the RCP4.5 (Representative Concentration Pathways 4.5) scenario are presented and uncertainties are assessed for the time period from 2021 to 2030. Compared with observations, annual mean temperature is overestimated while the variance is underestimated by most of the CMIP5 models in both East China and Shanghai. Analysis of precipitation indicates that the annual mean total precipitation simulated by most of the CMIP5 models are higher than that from observations, whereas the variance is higher in East China and lower in Shanghai than that from observations. For the historical simulation of climate change in Shanghai, the temperature trends simulated by 26 models and precipitation trends by 12 models are similar to the observation during 1986-2005. Based on the above results, eight CMIP5 global climate models have been selected to predict future extreme event changes in Shanghai. The results show that the number of extreme low temperature events (cold nights) is likely to decrease with the lowest level of uncertainty, while the number of extreme warm nights is likely to increase with a lower level of uncertainty. Large uncertainties exist in the projection of other climate variable indices, which may also change in the future. In particular, great uncertainties are found in the prediction of cold night index change. Both the frequency and intensity of heavy rain events are predicted to increase and uncertainties in such predictions are low.